Fuel injection systems

ABSTRACT

A fuel injection system for use with a multi-cylinder engine of the kind employing an ignition distributor includes a permanent magnet carried by a part of the distributor which rotates with the distributor shaft in use, and a plurality of magnetically operable switches positioned within the casing of the distributor adjacent the locus of movement of the permanent magnet. The switches are operated by the magnet in turn as the distributor shaft rotates and serve to control operation of means for supplying fuel to the cylinders of the engine.

United States Patent 1191 Longstaif-Tyrrell [4 1 Apr. 3, 1973 [541 FUEL INJECTION SYSTEMS 3,308,341 3 1967 McLaughlin ..123 14s DK 3,375,812 4/1968 Koda ..123/l48 E [75] Invent l 2,929,896 3/1960 Ronning ....200/19 M mmsham, England 3,284,740 11/1966 Neapolitakis... ....200/19 M 3,426,740 2/1969 Hufton ..l23/148 E [73] Ass'gnee' fig figs gzggz 3,430,616 3/1969 Glockler ..123/32 EA [221 Filed: Dec. 7, 1970 Primary Examiner-Laurence M. Goodridge Assistant Examiner-Cort R. Flint {21] Appl' 9562l AttorneyHolman & Stern [30] Foreign Application Priority Data ABSTRACT Dec. 17, 1969 Great Britain ..6l,435/69 A fuel injection System for use with a mum-cylinder engine of the kind employing an ignition distributor 52 US. Cl ..123/117 R, 123/32 EA includes Permanem magnet carried by 3 P Of the 51 Int. Cl. ..F02p 5/04, F02p 7/02 distributm which rotates with the distribut" shaft in [58] Field of Search 123/148 E, 32 EA, 148 DK, use, and a plurality of magnetically operable switches 148 123/32. 200/19 M positioned within the casing of the distributor adjacent the locus of movement of the permanent magnet. The switches are operated by the magnet in turn as the dis- [56] References Cited tributor shaft rotates and serve to control operation of UNITED STATES PATENTS means for supplying fuel to the cylinders of the engine. 3,5l7,142 6/1970 Bastam et al 123/32 EA 4 Claims, 2 Drawing Figures PATENTEDAPRQI ms 3 724 434 14 IA I FIG INVENTOR ATTORNEYS FUEL INJECTION SYSTEMS BACKGROUND OF THE INVENTION This invention relates to fuel injection systems for use with multi-cylinder combustion engines of the kind employing an ignition distributor.

SUMMARY OF THE INVENTION An ignition distributor for use in a multi-cylinder internal combustion engine employing a fuel injection system to supply fuel to the cylinders of the engine, the distributor comprising a casing having an open end, an insulating cap closing the open end of the casing, a plurality of fixed electrical contacts carried by the insulating cap, a distributor shaft rotatably mounted within the casing and rotatable by the engine in use, and a rotor arm mounted on the distributor shaft for rotation therewith past the fixed electrical contacts carried by the insulating cap to complete electrical circuit therebetween, the improvement including said distributor shaft having an end portion extending beyond the open end of the casing into the insulating cap, said rotor arm being mounted on the end portion of said distributor shaft, a switch carrier plate supported by the casing adjacent the open end thereof in close proximity to and below the rotor arm, a permanent magnet carried by the rotor arm and facing the carrier plate, and a plurality of magnetically operable switches positioned on the carrier plate in proximity to the locus of movement of the permanent magnet, said switches being operated, in use, by the magnet in turn as the distributor shaft rotates and serving to control the supply of fuel to the cylinders of the engine.

BRIEF DESCRIPTION OF THE DRAWINGS One example of the invention is illustrated in the accompanying drawings, wherein FIG. 1 is a fragmentary sectional view of an ignition distributor, and

FIG. 2 is a plan view of part of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION Referring to the drawings, a multi-cylinder internal combustion engine for a road vehicle includes an ignition distributor 11 having a casing 11 closed at one end by a molded insulating cap 12. The cap 12 carries a centrally disposed high tension input terminal 13 and a plurality of high tension output terminals 14, the terminals 14 being disposed in equiangularly spaced relation with one another in a circle having its center on the axis of the high tension terminal 13. The terminal 13 includes a carbon brush 15 which is spring urged into engagement with a conductive strip 16 on the upper surface of a molded synthetic resin rotor arm 17. The rotor arm 17 is carried at the free end of a rotor shaft 18 of the ignition distributor and rotates with the rotor shaft 18 of the distributor. Each of the terminals 14 includes a contact region adjacent the locus of the free end of the strip 16 on the rotor arm 17, and as the rotor arm 17 rotates, high tension electrical pulses supplied to the distributor from the ignition coil of the spark'ignition system of the engine are distributed to the spark plugs of the engine in turn via the strip 16 and the terminals 14.

A permanent magnet 19 is secured to the face of the rotor arm 17 remote from the cap 12 and rotates with the rotor arm 17. Mounted within the casing of the distributor adjacent the face of the rotor arm remote from the cap 12 is a printed circuit board 21. The printed circuit board 21 is annular, and is'so disposed that the shaft 18 of the distributor extends through a central hole 21a in the board 21. Mounted on the board 21 are first and second magnetically operable reed switches 22, 23 which are positioned diametrically opposite one another on opposite sides of the central aperture in the board 21, and adjacent the locus of movement of the magnet 19. Thus, as the shaft 18 rotates, the switches 22,23 are operated sequentially by the magnet 19.

Associated with each of the cylinders of the engine with which the distributor 11 is utilized is a respective inlet manifold which communicates with its respective cylinder by way of a conventional inlet valve operated in conventional manner. Communicating with each of the'inlet manifolds is a respective fuel injection nozzle which includes a solenoid operated valve operable to open the respective nozzle. Each of the nozzles is connected to a common high pressure fuel supply line to which fuel is supplied at constant pressure by a constant displacement pump. Thus, the length of time during which any of the injection nozzles remains open determines the quantity of fuel supplied to the respective manifold.

In a conventional four-stroke engine one complete engine cycle occurs for every 720 of crank shaft rotation. Thus, at some point in a single engine cycle, conveniently considered as 0 of crank shaft rotation, a predetennined number of the cylinders of the engine will have their inlet valves closed, while 360 of crank shaft rotation later the remaining cylinders will have their inlet valves closed. The reed switch 22 is electrically connected to a relay which controls opening of the solenoid operated valves of the injectors associated with the cylinders having their inlet valves closed at 0" of crank shaft rotation, while the reed switch 23 is electrically connected to a relay which controls opening of the solenoid operated valves of the injection nozzles associated with the remaining cylinders, which have their inlet valves closed at 360 of crank shaft rotation. The printed circuit board 21 is so positioned with respect to the cam shaft 18 that the reed switch 22 is operated by the magnet 19 at 0 of crank shaft rotation. Each reed switch is, of course, normally open, and is only closed momentarily by the magnet 19 as the magnet 19 passes the reed switch. Thus, as the magnet 19 passes the reed switch 22 at 0 of crank shaft rotation then the injection nozzles of said predetermined number of cylinders of the engine will be opened so that fuel is supplied into the manifolds associated with said predetermined number of cylinders. Similarly, at 360 of crank shaft rotation when the magnet 19 passes the reed switch 23 the injection nozzles of the remaining cylinders of the engine will be opened to supply fuel into the manifolds of the remaining cylinders of the engine. It will be appreciated that fuel injected into the manifolds of the cylinders of the engine will remain in the manifolds until the inlet valves of the respective cylinders open at the commencement of the induction stroke of the cylinders, whereupon the fuel will be drawn into the respective cylinders.

The quantity of fuel which is delivered into the manifolds is governed by a delay unit which controls the period of time during which the solenoid operated valves of the injection nozzles remain open after the nozzles have been opened by the reed switches 22,23. The delay unit is itself controlled in accordance with the fuel requirements of the engine at any given instant of time. The fuel requirement of the engine is determined by plurality of parameters including the depression in the air inlet of the engine, the speed of the engine, and the load'applied to the engine.

It will be appreciated that since the switches 22,23 are positioned 180 apart, then for the reed switch 23 to be triggered by the magnet 19 at a time equivalent to 360 of rank shaft rotation after the reed switch 22 has been triggered, the shaft 18 of the distributor must rotate at half the speed of the crank shaft of the engine.

This requirement is, of course, fulfilled in conventional ignition distributors for use with four stroke engines, since in order for the spark ignition function of the ignition distributor to be fulfilled, the shaft 18 does rotate at half the speed of the crank shaft of the engine. If desired more than two reed switches can be utilized.

The board 21 is secured to the casing 11 by screws which extend through slots in the board, the slots being provided with grommets which absorb vibrations in use. The reed switches on the board 21 are encapsulated in a rubber like material and the board is sufficiently pliable to provide vibration damping. Further electrical components may also be mounted on the board 21 such as, for example, to limit the current in the reed switches in use and to suppress transients. If desired the-grommets can be part of an annular gasket which is trapped between the cap 12 and the casing 11 so as to secure the board 21 to the casing 11 without the use of screws. Further the use of an annular gasket serves to seal the interface between the cap 12 and the casing 1 1 against ingress of dirt.

Having thus described my invention what I claim as new and desire to secure by Letter Patent is:

1. An ignition distributor for use in a multi-cylinder internal combustion engine employing a fuel injection system to supply fuel to the cylinders of the engine, the distributor comprising in combination a casing having an open end, an insulating cap closing the open end of the casing, a plurality of fixed electrical contacts carried by the insulating cap, a distributor shaft rotatably mounted within the casing and rotatable by the engine in use, a rotor arm mounted on the distributor shaft for rotation'therewith past the fixed electrical contacts carried by the insulating cap to complete electrical circuits therebetween, the improvement comprising said distributor shaft having an end portion extending beyond the open end of the casing and located within said insulating cap, said rotor arm being mounted on said end portion of the distributor shaft, a switch carrier plate supported by the casing across the open end of the easing in close proximity to and below the rotor arm, a

permanent magnet carried by the rotor arm and facing the carrier plate, and a plurality of magnetically operable switches positioned on the carrier plate adjacent the locus of movement of said permanent magnet, the switches being operated, in use, by the magnet in turn as the distributor shaft rotates and serving to control the sufiply of fuel to the cylinders of the engine.

2. e distributor as claimed in claim 1 wherein said plurality of switches comprises a pair of switches positioned on the carrier plate on diametrically opposite sides respectively of the distributor shaft.

3. The distributor as claimed in claim 1 wherein said switches are reed switches.

4. Thedistributor as claimed in claim 1 wherein said switch carrier plate is a printed circuit board. 

1. An ignition distributor for use in a multi-cylinder internal combustion engine employing a fuel injection system to supply fuel to the cylinders of the engine, the distributor comprising in combination a casing having an open end, an insulating cap closing the open end of the casing, a plurality of fixed electrical contacts carried by the insulating cap, a distributor shaft rotatably mounted within the casing and rotatable by the engine in use, a rotor arm mounted on the distributor shaft for rotation therewith past the fixed electrical contacts carried by the insulating cap to complete electrical circuits therebetween, the improvement comprising said distributor shaft having an end portion extending beyond the open end of the casing and located within said insulating cap, said rotor arm being mounted on said end portion of the distributor shaft, a switch carrier plate supported by the casing across the open end of the casing in close proximity to and below the rotor arm, a permanent magnet carried by the rotor arm and facing the carrier plate, and a plurality of magnetically operable switches positioned on the carrier plate adjacent the locus of movement of said permanent magnet, the switches being operated, in use, by the magnet in turn as the distributor shaft rotates and serving to control the supply of fuel to the cylinders of the engine.
 2. The distributor as claimed in claim 1 wherein said plurality of switches comprises a pair of switches positioned on the carrier plate on diametrically opposite sides respectively of the distributor shaft.
 3. The distributor as claimed in claim 1 wherein said switches are reed switches.
 4. The distributor as claimed in claim 1 wherein said switch carrier plate is a printed circuit board. 